I want to create a local switch for a particular version of OCaml
with my own patch applied using opam 2.  For opam 1.2.2, I did the
following rather low-level thing:

- create a directory: ~/.opam/compilers/4.04.0/4.04.0+my-ocaml
- place two files in this directory:
  4.04.0+type-debugger.comp, containing where opam can find my own patch
  4.04.0+type-debugger.descr, with a description of the compiler
- add an entry to ~/.opam/repo/compiler-index:
  4.04.0+my-ocaml default 4.04.0/4.04.0+my-ocaml

and then execute opam switch 4.04.0+my-ocaml.  Can I do the similar
thing in opam 2?  Thank you in advance for any info.

--
Kenichi Asai